A microbolometer is a type of uncooled sensor for detecting infrared (IR) radiation. Conventional microbolometers include a focal plane array (FPA) of detector elements, or pixels, each of which measures a change in electrical resistance while being exposed to thermal radiation. The change in resistance of pixels is converted into an image representing a two-dimensional temperature histogram at the scene focal point. Materials and processes currently used to produce uncooled IR detectors have substantial manufacturing variation, and inherent non-uniformities in pixel responsivity and offset often exist within conventional focal plane arrays. In order to compensate for wide manufacturing variation, non-uniformity correction (NUC) settings, also referred to as coarse-level equalization (CLE) settings, (per pixel) are typically applied to the imaging array, prior to integrating an image, (over a frame period) to compensate for these variations
For each video frame, a binary NUC value, per pixel, is transmitted from a host electronics circuit to the imaging array. As such, the transmission of NUC terms from the host to the imaging array has the properties of a video stream. Also, for each video frame, the results of imaging (called “imaging pixels”) are transmitted from the imaging array back to the host. Thus, there exists a persistent video transmission from the host to the FPA and a corresponding video transmission from the FPA to the host.
A typical microbolometer FPA requires control information. Typically, the control information is transmitted at the beginning of each frame. Control information is digital (binary) information that controls aspects of NUC application, windowing sizing, bias control information, video output formatting, and so forth. Often, this control information is transmitted serially, through a serial port.
As part of the progression to lower power and lower cost, microprocessor-based host electronics are being developed for microbolometer imagers. Newer microprocessor-based host electronics can reduce power and cost by using standardized formats and dedicated graphics processing and image process hardware. Such hardware operates on standardized interfaces.